1. Field of the Invention
The present invention relates to a drive control device for a motor and a drive control method, provided with a switching circuit for stopping operation of the motor.
2. Description of Related Art
Japanese Laid-open Patent Application Publication No. 2006-21645 discloses that in an electric power steering device, a semiconductor relay, that has a higher reliability than a mechanical relay, is provided in an output line of each phase connecting an inverter circuit and a motor, and the semiconductor relay is turned off to stop drive of the motor in order to shut off the drive of the motor.
However, in an operation state that a phase in the inverter circuit is controlled with a particularly high duty ratio as compared with other phases, in an output line of the phase with a particularly high duty ratio, boosting of a booster circuit is not performed or the boosting is insufficient during drive of the motor, so that the semiconductor relay may be turned off to stop operation of the motor.